I got my original problem fixed (sputtering, only running around 3500 rpms can be seen herehttp://www.mudmotortalk.com/mmt_v2/ ... =3&t=28475 ). spark plugs appeared to be the culprit, and it ran better upon taking it out. problem now is a slight (appx 300) rpm loss. could only run around 4150-4250, normally am running somewhere around 4400-4500. I am going to check the lash tonight or tomorrow to double check i set it correctly. could the lash being set too tight or loose cause this rpm loss?

Yep check valve lash. Valves too tight can keep the valve Open off the seat, and too loose wont open them far enough...

make sure your head gaskets aren't leaking as well, Joel. That could cause a slight rpm loss if the leak is minimal.

have a hunch it's the valves. Jim i checked when i was home for lunch and no obvious leaks. those gaskets got a good bit of attention when we reinstalled the heads.

got in the valves last night. one of the exhaust valves was way loose. hopefully that'll curtail my problem.

i hear ya! My valves were rattling pretty good after a few hrs. with the new heads. So bad the motor would sputter some after the switch was turned off. Just reset em after the ride last weekend. You finished with rugby season? Ready to put a ride or 2 together?